A light emitting diode (LED) emits a light having high brightness with low power consumption and thus has been used as a light source of various electric devices such as a display, a lighting device and the like. Recently, as a blue LED has been commercialized in addition to a red LED and a green LED, those LEDs of three RGB colors have been combined to create lights of various colors. Also, there is proposed a light emitting device employing such LED light sources emitting lights of different colors, and complementarily controlling light amounts thereof to thereby adjust chromaticity of a light of mixed color.
In these types of light emitting devices, when a chromaticity variation range of each LED light source is large, a chromaticity difference of the light of mixed color is also increased, which may cause the color difference in different light emitting devices. Thus, a lighting device has been disclosed, in which a light source for emitting a light of a non-white color is coated with a resin cap to firstly convert the color of the emitted light into the white color and then radiate a light of a desired color by virtue of a coated color filter (see, e.g., Japanese Patent Application Publication No. 4286935 (JP4286935B)). Using this lighting device can facilitate the acquisition of light sources because it is not necessary to limit light sources to those emitting lights of a same color.
However, in the lighting device described in JP4286935B, lights of various colors other than the white color are first converted into a white light, and thus parts of the lights are lost during the conversion, which may lower light emission efficiency. In particular, when emitting a light with a light emission spectrum significantly different from that of the white light, it is necessary to increase a concentration of a fluorescent material contained in the resin cap for conversion into the white color, which may greatly degrade light emission efficiency. In addition, in case of emitting a light of the white color by combination of three-color RGB LEDs, and then further converting the produced white color light into a light of different color, the color conversion is carried out twice, resulting in the increased loss of optical energy.